Polaroid 42" help

[Twins_Guy]

I just picked up a 42" polaroid model TLX-04244B and the dump, it looks brand new it still has the plastic wrap on the sides and the 42" sticker in the corner of screen. when I plug it in the red light comes on, I push the power button blue light comes on then it clicks then blue light flashes 6 times then stays blue. I get nothing coming on the screen, all the caps look good, does anyone know what the 6 flashes mean?

Thanks

[Caleb]

Re: Polaroid 42" help

Most common failure on this set seem to be the inverter circuits. Youtube has this video

[Twins_Guy]

Re: Polaroid 42" help

My power board does not look like that one in the video, here is a couple pics. is is possible to check the voltage of caps to see if there is a bad one? I went along and was getting readings on some and then one did not read anything and the ones after did not as well. could the one that read 0 be bad?

[budm]

Re: Polaroid 42" help

Pictures of the whole back side of the TV so we can see all the board. Check the DC voltage at the PSON pin when TV if off and when power switch is activated, use the chassis as the ground ref point for the meter. Please also read the basic LCD troubleshooting guide. This is the same power supply used in VIZIO TVs.

[Twins_Guy]

Re: Polaroid 42" help

Reading at pson is .17-.18 when off and 5.08 when on

[Caleb]

Re: Polaroid 42" help

That indicates the main is sending the signal to switch on the power supply. what other voltages are present on the power board? It looks like your board is supposed to have 12v and 24v in addition to the 5v you already tested. What are the voltages on those pins when the pson is at 5v

[budm]

Re: Polaroid 42" help

So you do have PS_ON, next we need to find out if the PFC Voltage booster circuit is working or not, you will have to get to the two pins of the main filter cap (the 450VDC Black cap under the heat sink), the voltage on the two legs should be about 370~400VDC when TV is powered up. The 12V/24V SMPS require this PFC voltage to run.

[Twins_Guy]

Re: Polaroid 42" help

The pins at 12v is 11.83 and 24 dont read anything. It reads a 1. On the left of the meter

[tom66]

Re: Polaroid 42" help

Try moving your meter to the next highest range, probably 200V. (24V is out of range for 20VDC range.)

[Caleb]

Re: Polaroid 42" help

I would try removing the connectors to the inverters one at a time and see if your 24v comes back, and Budm wants to know if the pfc is working.

[budm]

Re: Polaroid 42" help

There are three 24V output connectors: 24VA, and two 24VI. You must use the Ground pin of each connector for testing the output voltages just to be sure cause some time the Ground for 24V is not tied to the common ground of the power supply outputs.
Since you are getting the 12V, the 24v must be working since they are generated by the same power transformer.

[Twins_Guy]

Re: Polaroid 42" help

so I moved it to the 200 on the DCV and I get 24.8 and I have to use the 1000 and I get 535 on the big black cap.

[budm]

Re: Polaroid 42" help

"I get 535 on the big black cap" That cannot be right, are you measuring right at the two legs of the cap?
So you are getting 24VDC at all 3 connectors, if that is the case, the power supply is OK.
Need to look at voltages and signals at the inverter boards next if the 24V feeding the inverter boards are OK.

[Twins_Guy]

Re: Polaroid 42" help

I took the reading right were they are soldered on the board, yes I am getting 24.8 at all 3
so how do I check the inverter boards?

[budm]

Re: Polaroid 42" help

Remove the black covers so you can closely inspect the board for any blown fuses or components. Take good closed up pictures of the boards and around the connectors so we can see if it has any labels for the pins of the connectors.
If you can see the P/N on the boards, report that also.

[Twins_Guy]

Re: Polaroid 42" help

Well now I did it.. while checking the voltages the board moved and shorted out on the frame. big spark and now nothing, so I think I will just need to get a new board if I wanna get this one going,ugh..good thing I got it for free. I can see were the short was but nothing looks blown. Dang it.

[budm]

Re: Polaroid 42" help

You may have blown the main AC fuse.

[Twins_Guy]

Re: Polaroid 42" help

I tested it and there is continuity through it.

[Twins_Guy]

Re: Polaroid 42" help

So I did not know there was a fuse were the cord plugs in to the tv, I thought it was just the one on the board anyway, I was messing around this morning and found it...duh, anyway I got power back now, still getting the 6 blinking blue light, how come I cant seem to find what that code means..lol I cant be the only one that this has happened to.

[Caleb]

Re: Polaroid 42" help

If you've got access to a ring tester you can ring all the inverter transformers, they are a very common failure on these sets. You can try to test them using an ohm meter as well, test them all and look for the odd one out. I built this one for less than 10$ it has been a great meter for finding faults in inverter transformers.